The present invention relates to the field of hearing aid manufacturing and specifically relates to an assembly procedure for a completely-in-canal (CIC) design with floating components.
A custom hearing aid with a stereolithography (SLA) shell that includes a holding fixture for the receiver assembly has been described in prior art publications, such as U.S. Pat. No. 7,054,457 and U.S. patent publication no. 2004/0264723A1, both herein incorporated by reference. In these references, the process of shell manufacturing includes a virtual assembly that uses special 3-D design software. The operator of the 3-D software places all of the virtual components of the hearing aid into the virtual shell on a display of the computer system, therefore assuring the necessary space between the virtual components. Once the design is complete, the 3-D software produces an STL file that is used by an SLA machine to produce the physical shell. The STL file is a standard file format that is native to the stereolithography CAD software created by 3D Systems, and supported by many other software packages. Stereolithography utilizes a computer controlled UV laser beam to harden a photocurable liquid resin to produce 3-D copies of CAD models. The SLA computer may utilize the STL file format.
It is essential for the normal operation of a hearing aid that the receiver does not collide with any other components, otherwise feedback will occur and the hearing aid performance will suffer.
A typical construction of a CIC instrument includes floating components that do not have a rigidly fixed position, but rather are held in place by the flexible wires that connect them to the fixed components. The assembler of the hearing aid positions such components in order to fit them into the various shapes and sizes of CIC shells. The use of the floating components enables the assembler to close very small CIC instruments by placing the floating component into the available space inside the shell.
The main disadvantage of the floating components is that the operator does not have a clear guide for placing them. Even if the floating components are placed correctly during the virtual assembly, the operator can not put them precisely into the designated places. Therefore, floating components may collide with the receiver and cause the hearing aid to malfunction.
The prior does not address the problem of a possible collision of the receiver with floating components.